Wound dressings including a thin plastic film having an adhesive coating on one side are relatively widely used and adhesively coated thin plastic films are also used to affix medical devices other than wound dressings to the skin of a person, such as e.g. ostomy bags. A problem with thin adhesively coated plastic films is their tendency to wrinkle and adhere to themselves which make them very difficult to handle. In order to make such film dressings easier to apply to the skin of a person, they are provided with temporary stiffening layers which are removed once the film dressing has been applied. It is very difficult to apply film dressings without such stiffening layers. Known stiffening layers consist of paper (possibly silicone coated), plastic films or laminates of these materials.
EP 051935 describes a dressing made of polymeric film and a releasable layer made of paper providing stiffness to the dressing. U.S. Pat. No. 5,160,315 suggests kraft papers, polyethylene, polypropylene, polyester and composites of those materials as suitable materials for stiffening layers. The materials suggested provide stiffness to flexible film dressings but do not provide any guidance on choice of materials to solve the problem of conformability and difficulty in application to e.g. uneven body parts.
The more recent WO2008/019310 on the other hand presents a complex multi-layer conformable wound dressing having a permanently attached (i.e. not removable) support layer for application of the dressing to e.g. convex surfaces.
Even if existing stiffening layers make it possible to apply film dressings, usually without great problems, there is a relatively large risk of failure, creating of folds in the film when a film dressing is to be applied to uneven parts of the body of a person, such as heels, hands or elbows or even detachment of the dressing when it is worn.
EP 0 870 488 A2 discloses a foraminous stiffening layer having a multiplicity of wide openings separated by strips of stiffening material, whereby several of said strips have free ends along a peripheral edge of the film. Such a stiffening layer has many advantages but must be carefully handled during application due to the lack of stiffening strips between the free ends of such strips along at least two opposite peripheral edges of the film.
The objective of the present invention is to improve such removable stiffening layers in wound dressings or other medical devices so that such devices are more easy to apply and so that the risk of failure or the creating of folds when the dressing or the medical device is applied to skin is eliminated or at least greatly reduced.